@article{MAT_1966_10_4_a5,
     author = {H. Busemann},
     title = {Extremals on closed hyperbolic space forms},
     journal = {Matematika},
     pages = {140--145},
     publisher = {mathdoc},
     volume = {10},
     number = {4},
     year = {1966},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/MAT_1966_10_4_a5/}
}